A Control Strategy with Series-Parallel Inverter for Micro-Grid Operation

2014 ◽  
Vol 1044-1045 ◽  
pp. 677-680
Author(s):  
Gui Ying Liu ◽  
Yong Guang Gui ◽  
Shi Ping Su ◽  
Qian Luo ◽  
Jiang Wu ◽  
...  
Keyword(s):  
Control Strategy ◽  
Control Method ◽  
Operation Mode ◽  
Droop Control ◽  
Three Phase ◽  
Islanding Operation ◽  
Integral Controller ◽  
Micro Grid ◽  
Grid Operation ◽  
Parallel Inverter

For the different operation mode of micro-grid, an improved droop control method and a parallel inverter was proposed depending on the study of micro-grid inverter. Grid-connected interface contains a series inverter and a parallel inverter, and can be switched to select different work mode. The parallel inverter can eliminate harmonic, compensate three-phase imbalanced current to improve the quality of the power delivered to the utility grid. In islanding operation mode, the improved droop control strategy was applied, where an integral controller was introduced. So it can reduce the inverter output voltage amplitude. Thereby it can restrain circulation and realize the power of self-distribution. The effectiveness and feasibility are verified by the simulation result.

Single-Phase Independent Droop Control Strategy in Low-Voltage Microgrid

2015 ◽  
Vol 733 ◽  
pp. 684-690 ◽  
Author(s):  
Zhong Lin Zhang ◽  
Tao Wang
Keyword(s):  
Control Strategy ◽  
Single Phase ◽  
Control Method ◽  
Low Voltage ◽  
Frequency Stability ◽  
Droop Control ◽  
Level Control ◽  
Independent Control ◽  
Three Phase ◽  
Micro Grid

In the three-phase four-wire low-voltage micro grid, three-phase imbalance usually happens because of a large number of single-phase loads. In this situation, the traditional control method cannot effectively control the voltage and frequency stability when the low-voltage micro grid operates in the island mode. According to the characteristics of the three-phase four-wire low-voltage micro grid, this paper designs a single-phase independent control based on the droop control. This paper firstly uses the improved droop control considering that the impedance characteristic of the low voltage micro gird is mainly resistance, and also designs single-phase independent control to ensure the control system have the ability to run under the unbalanced loads. Then this paper designs a two-level control strategy to control the voltage and frequency in the micro grid during the island operation. Finally, a simulation analysis based on the proposed method is used to prove the effectiveness. A micro grid is set up on PSCAD, and verifies the effectiveness of the single-phase control strategy based on the improved droop control. The proposed method can also realize the requirement of the voltage and frequency stability during the island operation. At the same time, the control method proposed in this paper can achieve the control objective under the condition of unbalanced three-phase.

Comprehensive Control Strategy and Simulation Research on Micro Grid

2014 ◽  
Vol 602-605 ◽  
pp. 2609-2614
Author(s):  
Yu Long Wang
Keyword(s):  
Control Strategy ◽  
Power Distribution ◽  
Hot Spot ◽  
Green Energy ◽  
Simulation Software ◽  
Regulation Mechanism ◽  
Droop Control ◽  
Simulation Research ◽  
Micro Grid ◽  
Grid Operation

Micro grid can integrate various distributed generators and provide local load with green energy. Therefore, it becomes a hot spot of research in every country all over the world. Due to small inertia, large number of models, big difference among internal electric sources of Micro grid operation, it is more difficult to keep stabilization of voltage frequency of common points in the network, and more complicated to control the problems. The article puts forward the improved droop control strategy based on distributed power supply layer, on the basis of traditional droop control, it increases the feed forward regulation mechanism so as to change the droop coefficient, increase the power regulation scope, speed up the common point frequency voltage stability and improve the control precision, which has realized the specific control of power output when the Micro grid synchronizes and closes, as well as the purpose of power distribution according to load demand for islanding. Finally, we use power system simulation software PSCAD/EMTDC V4.4 to verify the practicability of the proposed scheme.

The Study of Hierarchical Control Method for Micro-Grid Control

2012 ◽  
Vol 260-261 ◽  
pp. 482-486
Author(s):  
Yong Yi Wu ◽  
Shuang Hu Wang
Keyword(s):  
Energy Management ◽  
Control Strategy ◽  
Management System ◽  
Control Method ◽  
Operation Mode ◽  
System Optimization ◽  
Energy Management System ◽  
Control Analysis ◽  
Control Command ◽  
Micro Grid

The micro-grid structure and operation mode are analyzed in this paper. By listing micro-grid typical operation mode, and explains the energy management system, micro-grid controller, electric primary equipment is how to coordinate between control. Analysis of the usual method for the energy management system optimization control strategy will be passed to the micro-grid controller. A kind of brand-new control command transmission mode is put forward for improving the micro-grid control strategy by the efficiency.

Performance Improvement of SVPWM-Based Three-Phase Grid-Connected Inverters

2013 ◽  
Vol 732-733 ◽  
pp. 1261-1264
Author(s):  
Zhi Lei Yao ◽  
Lan Xiao ◽  
Jing Xu
Keyword(s):  
Dynamic Response ◽  
Control Strategy ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Grid Current ◽  
Current Controller ◽  
Three Phase ◽  
Reference Grid ◽  
Grid Connected Inverter

An improved control strategy for three-phase grid-connected inverters with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d-and q-axes grid currents is interacted in the traditional control method, and the waveform quality of the grid current is poor. As the reference output voltage cannot directly reflect the change of the reference grid current with the traditional control strategy, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d-and q-axes grid currents in the decoupled components of the grid current controller are substituted by the d-and q-axes reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results show that the grid-connected inverter with the improved control strategy has high waveform quality of the grid current and fast dynamic response.

Control Strategy of Wind Photovoltaic and Energy Storage System Stability Running

2013 ◽  
Vol 336-338 ◽  
pp. 547-550
Author(s):  
Ji Hong Zhang ◽  
Zhen Kui Wu ◽  
Hua Li ◽  
Han Shan Li
Keyword(s):  
Energy Storage ◽  
Distributed Generation ◽  
Control Strategy ◽  
Control Method ◽  
Storage System ◽  
Energy Storage System ◽  
System Stability ◽  
Mathematics Model ◽  
Generation Efficiency ◽  
Micro Grid

Micro grid may exert adequately distributed generation efficiency, and that wind Photovoltaic and Energy Storage is a key equipment in the micro grid. Aiming at the distributed generation existing intermittence and randomicity characteristic, the paper discussed the micro grid P/Q control method under the connection grid state and the micro grid U/F control method under the disconnection grid state. It also studied the distributed generation parameters variational law under the micro grid different run mode, and built the correlative mathematics model and tested by simulation. The results show: the control strategy ensured the mice grid running stably, and achieved the system anticipative design request, and offered theory foundation for the distributed generation extend application.

scholarly journals Capacity Limitation Control of Multiple Bi-directional DC-DC Converters for Micro Grid Application

2015 ◽  
Vol 2 (1) ◽  
pp. 61 ◽  
Author(s):  
S. J. Chiang ◽  
Yu-Min Liao ◽  
Ke-Chih Liu
Keyword(s):  
Power Management ◽  
Control Method ◽  
Droop Control ◽  
Control Methods ◽  
Power Capacity ◽  
Capacity Limitation ◽  
Current Sharing ◽  
Parallel Control ◽  
Micro Grid ◽  
Bus Voltage

The micro grid system requires battery for energy storage and power management. In which, the bi-directional DC to DC converter is the key component for maintaining the DC bus voltage and controlling the charge and discharge of the battery with or without grid support. Parallel control of multiple DC to DC converters is a critical technique to enlarge the power capacity. This paper presents two capacity limitation control methods that multiple DC to DC converters can be paralleled with distributed battery banks. The first method is the capacity limitation control with cascaded load current sense needing no control interconnection. The second method is the capacity limitation control with master-slave and cascaded current command limitation. Two methods are presented to solve the limitation of droop control method and active current sharing method respectively, and can be extended without converter number limitation theoretically. Three prototype 240W bidirectional half-bridge DC to DC converters are built and paralleled in this paper. The proposed method is confirmed with some measured results.

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